The offer of some clinics to treat all kinds of illness using injections of stem cells may soon come to an end. For several years, many businesses have offered the approach—which often takes stem cells from one tissue and places them in an unrelated organ—to treat everything  from autism to cerebral palsy. But as we’ve reported in the past, there’s little evidence it works, and the procedures can even prove harmful. And while patients used to travel overseas for the treatment, centers offering the technique have recently begun to proliferate across America, too.

Now, though, the FDA is clamping down. It's announced that it raided the labs of one clinic, called StemImmune, in order to seize vials of a live virus that the company was mixing with stem cells and injecting into people. It's written a letter to U.S. Stem Cell Inc. in Florida, warning it that its injections of stem cells into spinal cords could put patients at risk. And in a statement from FDA commissioner Scott Gottlieb, the administration says that it plans to introduce new policies to stamp out "deceptive, and sometimes corrupt, assurances to patients based on unproven and, in some cases, dangerously dubious products."